Study of the Structure of Quinoline Extracts from Yubari Coal by High Resolution

Abstract

As part of a series of studies of coal constitution based upon the hydrogen distribution of coal extracts from their NMR spectra, in the present paper the constitution of quinoline extracts of Yubari coal were studied. The coal sample was prepared as follows:Lump Yubari coal obtained directly from Yubari No.2 Mine was crushed and processed with a ZnCl2 solution of a specific gravity of 1. 24. A very low ash coal sample was obtained and its yield was 69 percent of the parent lump coal. This was used for the present study of coal constitution.The coal sample was extracted with quinoline at 300-400°C for 4 hrs. under a pressurized atmosphere of nitrogen. The yield of quinoline extracts, after being separated from the solvent and died, was 90-98 percent of the coal sample. In order to prepare the samples for the measurement of NMR spectra of the quinoline extracts in deutero-py ridine solvent, the quinoline extracts were again extracted with pyridine at room tempe rature. The yield of pyridine extracts thus obtained was 32-75 wt.percent based upon the dry Yubari coal sample (Tables 1 and 2). The pyridine extracts above described and a pyridine extract obtained directly from the Yubari coal sample itself were redissolved into deutero-pyridine, C5D5N. The C5D5N solutions (approx. 10 wt. %) of these coal extracts thus prepared (NMR Samples No.1-5) were examined b NMR spectroscopy at 60Mc. From the contents of the different types of hydrogen atoms estimated from NMR spectra and the result of elementary analysis, various structural parameters were given for the coal extracts, i. e. NMR samples No.1-5 (Table 6). In the mean structure as revealed from these structural parameters, there seems to be only a slight difference between the quinoline extracts (NMR samples No.1-4) and the direct pyridine extract (NMR sample No.5). However a detailed consideration shows that the carbon aromaticity and the average number of condensed aromatic rings in the mean structure of these coal extracts tend to increase with the temperature level of the quinoline extraction of coal.